ZWART - STABILO BIONIC WORKER DESIGNED FOR PROFESSIONALS - Where comfort, durability, reliability and extended use are concerned, the STABILO worker+ rollerball pen is a must. It is the perfect tool for any professional who needs the flexibility of a liquid-ink pen that is ideal for both writing and design activities. COMFORTABLE WRITING - The whole pen shaft has a non-slip surface, making extended periods of intense work fly by without aching or cramping. HIGH-QUALITY ROLLERBALL TIP - This rollerball is the high-quality solution for the exacting professional, whether at work, at school or in the studio. SMOOTH WRITING - The medium tip (0.5 mm) ensures a smooth feeling of writing. FOUR DIFFERENT PEN INK COLORS - It comes in four popular ink colors: black, blue, green and red with either a 0.3mm (fine) or a 0.5mm (medium) indestructible tip. All four pens come in a bright orange shaft.